Carotenoids have recently been postulated to prevent coronary heart disease (CHD) by the prevention of oxidation of low-density lipoproteins to more atherogenic compounds. The proposed study will test this hypothesis by examining data from the Lipid Research Clinics Coronary Primary Prevention Trial (LRC-CPPT) and Follow-up. This randomized, placebo-controlled trial examined the effectiveness of cholestyramine in reducing CHD among hyperlipidemic men. Baseline serum carotenoid measurements and CHD events/deaths are available for this cohort of over 3700 men with 14 year of follow-up. The relationship between baseline serum carotenoids and subsequent CHD will be examined in the placebo group adjusting for smoking and other important covariates. This relationship will also be studied in the cholestyramine group to assess the interaction between the lipid lowering and carotenoid lowering effects of cholestyramine. The proposed study will add important information concerning the possibility of using carotenoids to prevent CHD.